SB Disco for 2 strings (was RE: ST XR series, anyone tried on yet? ) [RE-wre

[Brian C. White]

Mo,

Take a look at Connect Energy's PCBHV4D, I think we may have the 
disconnect you are describing.

Contact me off list if you have questions

Brian C. White
Mechanical Design / Technical Sales
Connect Energy
www.connectenergy.org

If I can be of further help, please contact me directly.
530-271-1919 x.106
brianw at connectenergy.org


mrousso at urbanrefuge.com wrote:
> In my opinion a really nice dc disco would also have a
> combiner box built in.  So, if you are running two
> strings of 24vdc panels you can combine them before
> the SB, provide string fusing, and have only a single
> disco to contend with.  Is my thinking flawed -- any
> other suggestions??  We are doing quite a bit of 2
> string installs with a single SB.
> 
> Thanks!
> Mo
> --- jberdner at sma-america.com wrote:
> > William:
> > 
> > Two of our customers have been testing the new XR's
> > which are
> > replacements for older ST's.
> > They both tell me they are better than the ST in
> > steady state conditions
> > (clear sky) but still have trouble if there are any
> > clouds in the sky.
> > This is really key since we don't all have perfectly
> > clear sky days.
> > The MPPT seems to get lost if the irradiance is
> > changing.
> > Now the XR's are only 10 to 15% behind the Sunny Boy
> > instead of 20 to
> > 25% for the older ST's.
> > 10% does not seem like much but would you seriously
> > consider an inverter
> > that was 80 to 85% efficient instead of one that was
> > 94.4 ?
> > By the way - I use 92.5% for design by the way not
> > 94.4 peak as in the
> > CEC calculation
> > 
> > To address the comment re: internal disconnects.
> > We tried to put one in but we can't' get a
> > conclusive go ahead from UL.
> > The inverters are considered serviceable items and
> > therefore you have to
> > be able to remove it form the installation and leave
> > things in a safe
> > condition.  
> > Right now this means an external disconnect until UL
> > says otherwisw.
> > I know the ST /XR does it but that does not mean we
> > want to do it too.
> > We operate at higher voltages and I want to be safe
> > rather than sorry.
> > I am working on lower cost disconnects and will let
> > you know when we get
> > one.
> > 
> > If you have any questions, or if I can be of any
> > further assistance,
> > please do not hesitate to contact me.
> > 
> > Best Regards,
> > 
> > John Berdner
> > 
> > SMA America, Inc.
> > 20830 Red Dog Road
> > Grass Valley, CA  95945
> > 530.273.4595 (voice)
> > 530.274.7271 (fax) 
> > 
> > 
> > -----Original Message-----
> > From: William Miller [mailto:wrmiller at slonet.org] 
> > Sent: Thursday, June 20, 2002 9:32 PM
> > To: RE-wrenches at topica.com
> > Subject: Re: ST XR series, anyone tried on yet?
> > [RE-wrenches]
> > 
> > Bob-o:
> > 
> > We used to joke that the person who recommended the
> > meters on the ST was
> > bound to get fired.  I guess he or she did get
> > fired.
> > 
> > I am not impressed that the STs no longer have the
> > metering we were used
> > to.  I thought this was one of only two advantages
> > the ST had over the
> > Sunny Boy (the other is built in disconnects).
> > 
> > Also, it sounds like you are assuming the shut-downs
> > are caused by grid
> > problems.  Do you have evidence of that?  (After
> > watching the original
> > ST
> > inverters shut down hundreds of times, I am
> > convinced it was because the
> > MPPT algorithm was too aggressive and, after loading
> > the panels too
> > much,
> > the voltage collapsed.  You could see the PV volts
> > cave just before the
> > shutdown.)
> > 
> > I did a  back-to-back comparison between the
> > original ST2500 and the
> > SB2500
> > and found the ST to be about 10% less efficient than
> > the SB.  Sounds
> > like
> > we may be in the same ballpark.  This comparison was
> > relevant for the
> > periods of time that the ST was running.  Frequent
> > shut-downs and the
> > subsequent time-outs could reduce the efficiency
> > significantly.
> > 
> > This was actually a trick question as I installed
> > two XRs yesterday, but
> > wanted to reserve judgement until I heard from
> > others.  One of my two
> > inverters had a missing lower line on the display. 
> > This was also
> > disappointing as I have many of display failures in
> > the original STs.
> > 
> > I'm looking for a reason to use STs rather than
> > Sunny Boys and I haven't
> > found one yet.  With the SB1800s now shipping (they
> > are shipping, aren't
> > they?) the 1500 no longer fills any kind of gap in
> > the product line.
> > 
> > Thanks for your responses,
> > 
> > William Miller
> > 
> > 
> > 
> > At 10:20 AM 6/20/02 -0700, you wrote:
> > >William,
> > >We probably ARE all fiends, at that!
> > >I've got six of the STXR 2000 in parallel on a big
> > system in Redding. 
> > >We had a few fits and starts, but at this point
> > they all seem to be 
> > >playing nicely. I'm seeing about 65-68% conversion
> > from PV nameplate 
> > >watts to ac watts out. That's about 10% less than
> > the Sunny Boy will 
> > >give you, but you've got to figure that 48V to 240V
> > step up is going 
> > >to be less efficient anyway.
> > >Roy,
> > >Yes, the meter built into the XR shows cumulative
> > DAILY watts (resets 
> > >every night) ONLY. If you want instantaneous watts,
> > volts, etc., you 
> > >have to have the STXR remote. Xantrex claims that
> > they changed the 
> > >display because they were getting too many calls
> > from end users 
> > >reading it and being confused. Yeah, yeah... maybe.
> > On the other 
> > >hand, Xantrex is a MARKETING company, so....
> > >One cool thing about the remote is the error codes
> > feature. It will 
> > >tell you how many times the inverter has gone off
> > line for 5 minutes 
> > >due to poor grid voltage, frequency, overheating,
> > etc. It's amazing 
> > >how often that happens. So much for grid stability.
> > Unfortunately, 
> > >the codes are not resettable to zeros (dumb) so you
> > have to keep a 
> > >running tally from looksee to looksee.
> > >Bob-O
> > >
> > 
> >
> __________________________________________________________________
> > William Miller
> > Miller Power and Communications
> > PO Box 50, Santa Margarita, CA 93453
> > Voice :805-438-5600		Fax: 805-438-4607	VMail:
> > 805-546-4875
> > email: wrmiller at slonet.org
> > http://millerpowerandcomm.com
> > License No. C-10-773985
> >
> _____________________________________________________________
> > Compatibility:
> > Word processor: WP7
> > Spreadsheet: Quatro Pro 7
> > CAD: Microstation 95, DXF, Visio 4.1T
> >
> _____________________________________________________________
> > "Every decent man is ashamed of the government he
> > lives under."
> >                                     H. L. Mencken
> >
> __________________________________________________________________
> > 
> > - - - -
> > To send a message: RE-wrenches at topica.com
> > 
> > Archive of previous messages:
> > http://www.topica.com/lists/RE-wrenches/
> > 
> > List rules & etiquette:
> > http://www.mrsharkey.com/wrenches/etiquete.htm
> > 
> > Check out participant bios:
> > www.mrsharkey.com/wrenches/index.html
> > 
> > Hosted by Home Power magazine
> > 
> > Moderator: michael.welch at homepower.com
> > 
> > - - - -
> > To send a message: RE-wrenches at topica.com
> > 
> > Archive of previous messages:
> > http://www.topica.com/lists/RE-wrenches/
> > 
> > List rules & etiquette:
> > http://www.mrsharkey.com/wrenches/etiquete.htm
> > 
> > Check out participant bios:
> > www.mrsharkey.com/wrenches/index.html
> > 
> > Hosted by Home Power magazine
> > 
> > Moderator: michael.welch at homepower.com
> > 
> >
> > 
> > 
> > 
> 
> 
> =====
> Mo Rousso
> Urban Refuge, Inc.
> 760.451.9374 (v) 760.451.9784 (f)
> mrousso at urbanrefuge.com
> www.urbanrefuge.com
> 
> __________________________________________________
> Do You Yahoo!?
> Yahoo! - Official partner of 2002 FIFA World Cup
> http://fifaworldcup.yahoo.com
> 
> 
> 



Brian C. White
Mechanical Design / Technical Sales
Connect Energy
www.connectenergy.org

If I can be of further help, please contact me directly.
530-271-1919 x.106
brianw at connectenergy.org

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9
Or send an email to: RE-wrenches-unsubscribe at topica.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================